The Effect of Aposematic Coloration on the Food Preference of ...

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V. Aphelocoma coerulescens - Potential PredatorAphelocoma coerulescens, commonly called the Florida scrub jay, is a nationallyclassified threatened species <strong>of</strong> bird endemic to the state <strong>of</strong> Florida. In 1993, this species wasestimated to have lost 90 percent <strong>of</strong> its original population, resulting in fewer than 4000 breedingpairs remaining throughout its habitat.This decline has been most directly attributed to the rapidloss and destruction <strong>of</strong> the state's oak scrub habitat, which is essential to the survival <strong>of</strong> the birds(<strong>The</strong> Nature Conservancy and Audubon <strong>of</strong> Florida 2001).Scrub jays prefer to live in habitatcharacterized by low-growing shrubs, which serve as protection against nest predation fromabove, and ground that is15-20 percent exposed sand, a property <strong>of</strong> the land that allows the birdsto cache foods with little difficulty.This habitat preference limits the areas that can sustain scrubjays to only seven locations along the Coastal Ridge <strong>of</strong> Florida (<strong>The</strong> Nature Conservancy andAudubon <strong>of</strong> Florida 2001).Scrub jays practice a unique behavior called cooperative breeding, in which <strong>of</strong>fspringremain with the parents and share the responsibilities <strong>of</strong> gathering food and caring for the nextseason's young.Only when they find a mate do they leave the cooperative breeding unit tobegin one <strong>of</strong> their own.<strong>The</strong>y commonly feed on a wide range <strong>of</strong> food sources that variesaccording to whether or not it is the breeding season. During non-breeding months, the speciesfeeds primarily on large acorns, seeds, fruits, and nuts, many <strong>of</strong> which are stored earlier in theseason.<strong>The</strong>ir diet is expanded during the breeding months between March and June to includesmall insects and invertebrates as well as bird eggs and nestlings <strong>of</strong> other species (Ehrlich et al.1988). This diet indicates that Aphelocoma coerulescens shows interest in seeds and legumesand, therefore, would possibly respond to the warning signals <strong>of</strong> noxious seeds like those <strong>of</strong>Abrus precatorius.
VI.<strong>The</strong> Study - Potential <strong>Aposematic</strong> <strong>Coloration</strong> Predator-Prey InteractionThis research focuses on ideas similar to those presented earlier: namely the avoidance <strong>of</strong>red and black color patterns by predators and the association <strong>of</strong> those patterns with potentialdanger.However, the present study deals with an interaction that has not been evaluated: that is,the interaction between Abrus precatorius and Aphelocoma coerulescens.Both species havecomparable distributions throughout Florida, making the likelihood <strong>of</strong> contact with each otherplausible.<strong>The</strong> study examines the effect that red and black color patterns, similar to those <strong>of</strong> theaposematic jequirity beans, have on the food choice <strong>of</strong> scrub jays.Through the use <strong>of</strong>constructed model seeds, itassesses the interaction based on color alone, with no otherinterfering signals.This detail, combined with known information about aposematic colorsignals and their functions, makes itis possible to predict the responses <strong>of</strong> Aphelocomacoerulescens and to interpret the significance <strong>of</strong> those responses.If the birds avoid the red andblack patterned model seeds, itserves as an indication that the same aposematic color pattern inAbrus precatorius is a sufficient signal to warn predators not to attack.If, on the other hand, thebirds do not discriminate against the red and black seeds, itsuggests that the color pattern doesnot autonomously evoke avoidance, but depends on a combination <strong>of</strong> other signals.Thus, thisresearch is designed to determine if the coloration <strong>of</strong> Abrus precatorius is aposematic.
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Page 25 and 26: 21Patocka, J.,2001. Abrin and ricin

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